Magnetostatic device



June 11, 1963 P. BURSTOW ETAL MAGNETOSTATIC DEVICE Filed Oct. 6, 1958 m/va/vrafs F/E/eeg 50m CLAUDE Mam/v 5 AWE/OVA? i0| i i BR:

United States Patent 3,093,746 MAGNETOSTATIC DEVICE Pierre Burstow, Paris, and Claude Monin, Villennes-sur- Seine, France, assignors to Compagnie Industrielle des Telephones, Paris, France, a French corporation Filed Oct. 6, 1958, Ser. No. 765,474 Claims priority, application France Oct. 28, 1957 1 Claim. (Cl. 307-88) The present invention relates to a magnetostatic device by means of which it is possible to select a single member from a plurality of members having the same characteristics. The selection is effected by means of magnetostatic relays having no moving contacts. The device is applicable notably in automatic telephony and telegraphy and in remote control.

Independently of selecting devices comprising either rotary switches or electromagnetic relays having moving contacts there is known a device, disclosed in French Patent No. 1,138,493 of December 8, 1955, an electromagnetic selecting device in which magnetostatic relays having no moving contacts are employed. In this device, the relays are controlled by a pilot blocking relay, which has certain disadvantages from the technical viewpoint.

The present invention has for its object to'provide a selecting device of this type which employs magnetostatic relays and of which the operation is improved, while at the same time the cost is reduced, by virtue of the omission of the pilot relay.

The device according to the present invention is characterised by the fact that the relays are grouped in parallel and each feed through a feedback winding into a separate load, the free ends of which are connected to a common point, which is connected to the series-connected blocking windings of all the relays.

The separate resistances are so chosen that the strength of the current of one relay in the operated or active state is sufficient to prevent another relay from pulling up, but if two or more relays are simultaneously in the operated state the total current fed by the relays in the operated state is such that all the relays in the operated state return to the unoperated or inactive position. It is then the most rapidly acting relay which is the first to return to the operated state and which blocks the other relays in their inactive position, as long as it itself remains operated.

Further features and advantages of the invention will become apparent from the description hereinafter given with reference to the accompanying drawings, which show by way of example one constructional form of a device according to the invention:

FIGURE 1 illustrates diagrammatically a device according to the invention, and

FIGURE 2 is the operating diagram of the device.

In FIGURE 1, the dotted enclosures R R R R represent magnetostatic storage relays, for example of the type defined by applicants in French Patent No. 1,127,470 of May 27, 1955, and in the French Patent 1,160,506 filed on November 9, 1956, or in the corresponding United States Patent 2,946,896, for Magnetostatic Relay. Each relay comprises at least one saturable magnetic circuit on which are wound an operating winding fed in series with a rectifier from an alternating-current source and control windings. Each relay comprises an output circuit, S in the case of the relay R S in the case of the relay R S in the case of the relay R through which rectified current flows or does not flow depending upon the cur-rents applied to the control windings. The saturable magnetic circuit for each relay is illustrated as an annular core and for the core associated with relay R there are illustrated wound thereon feedback winding e bias winding e primary control winding e holding winding e and blocking winding e in addition to an operating winding. Similar windings are provided for each of the other magnetic cores but with appropriate changes in the numerical subscripts designating particular windings. The blocking windings e e e of the relays R R R R are connected in series. Connected to the output point S of the relay R is the feedback winding e the other end of which is connected to an individual load r Connected to the output point S of the relay R is the feedback winding e of which the other end is connected to an individual load r The same is the case with the other relays R R R The outputs of the individual loads are connected to a common point P (the resistances of the links P P P P P P being assumed to be negligible), which is in turn connected to the series blocking windings e e e of the various relays.

Any operated relay, for example R feeds from the output point S a current which flows through the negative winding feedback e across the resistance r and y then through the series blocking windings e e e An unoperated relay does not feed any current into the blocking circuit. Any counterclockwise directed arrow adjacent a relay winding indicates that if a current flows through the winding it tends to bring the relay to the operated condition (positive ampere-turns). On the other hand, a clockwise oriented arrow adjacent a winding indicates that if a current flows through the winding it tends to return the relay to the inactive state (negative ampere-turns) The windings e e e e are bias windings of the various relays, which permit of bringing the latter to a common initial setting.

The windings e e e e are control windings which tend to bring the relays to the operated condition, while the windings e e 8 e are holding windings which tend to cause the operated relay to fall back or to maintain the relay in the inactive condition. The resistance of all the series blocking windings e e e e is small in relation to the individual resistance of a relay, so that the potential of the common point is only slightly difierent from that of the second pole of the relay.

The operation of the device will hereinafter be eX- plained with reference to FIGURE 2, which is the operating diagram of a magnetostatic storage relay. The control ampere-turns N l are plotted along the axis of the abscissae and the output current I is plotted along the axis of the ordinates. It will be assumed that FIG- URE 1 represents a number of ringing relays R R R forming a group in accordance with the arrangement indicated. The bias windings of these various relays have set the operating point at the point 0. All these relays are therefore in the inactive state. If the subscriber whose ringing relay is, for example, the relay R calls, there flows through his control winding e current which gives positive ampere-turns represented by the vector C The operating point changes from the point to the point P and the relay R is operated or active and consequently supplies a current i. The current i produces in each of the series windings e e e negative ampere-turns which are represented by a vector E in the case of the operated relay and by a vector B (of the same size as B for the inactive relays. It will thus be seen that the operating point changes from the point P to the point P in the case of the operated relay, while in the case of the inactive relays the operating point changes from the point 0 to the point A Under these conditions, if another subscriber calls, for example the one corresponding to the relay R the ampere-turns produced, which are represented by the'vector C will bring the operating point from point A to the point P but the relay R will not become active.

Therefore, any operative relay blocks all the other relays of the group which are in the inactive state, as long as it itself remains operative.

Assuming now that a plurality of relays, for example the relays R and R have been simultaneously operated, each of them then supplies a current i and these currents will be summated to form a current 2i in the common part of the circuit, that is to say, in the series blocking windings e e e e The ampere-turns produced are represented by vectors ZB in the case of the operative relays or 2B in the case of the inactive relays, which respectively change the operating points from P to the point 0 in the case of the operative relays and from the point 0 to the point A in the case of the. inactive relays. Therefore, the relays which are operative change to the inactive state.

It will be obvious that no two relays can ever have exactly the same internal characteristics, one of the relays being re-operated before the other and eliminating it in accordance with what has been stated in the foregoing. The example taken here is that of a group of ringing relays. It is obvious that the invention is applicable to other groups of members, for example to the selection of a free line from a plurality of lines of like direction, and in general to the selection of a single member from a plurality of members having the same characteristics. It is also possible for the individual resistances such as r r r to be included in the feedback windings themselves.

We claim:

A magnetostatic selecting device including a plurality of magnetostatic relays, each magnetostatic relay comprising a saturable magnetic circuit, a main operating winding wound on the magnetic circuit with an output connected thereto, and additional windings wound on the magnetic circuit including a control winding, a feedback winding and a blocking winding, each relay being susceptible to assume active and inactive states of operation respectively supplying different current values in its output circuit, means for applying a control current to the control windings of each of the relays to modify its state of operation, the feedback winding of each of the relays being connected in series in the output circuit of said relay, means connecting the output circuits of the relays to a common point, means connecting the blocking windings or said relays in series to said common point with said windings being so constructed and arranged that when all the relays are in the inactive state of operation a control current is applied to a control winding of one of the relays, said relay is placed in the active state of operation and its output circuit supplies a constant direct current in the blocking windings of the other relays to keep them inactive.

References Cited in the file of this patent UNITED STATES PATENTS 2,682,615 Sziklai et al. June 29, 1954 2,719,773 Karnaugh Oct. 4, 1955 2,772,357 An Wang Nov. 27, 1956 2,946,896. Alizon et al. July 26, 1960 

